Challenging diagnosis: Low-grade sinonasal adenocarcinoma masquerading as capillary haemangioma

ABSTRACT Sinonasal non-intestinal-type adenocarcinomas (LG-SNACs) are rare, low-grade malignancies that arise from the seromucinous glands in the sinonasal tract. These tumours are often diagnosed in patients presenting with persistent nasal obstruction and recurrent epistaxis. We present the case of a 34-year-old male who presented with nasal obstruction and recurrent bleeding, eventually diagnosed with low-grade non-intestinal sinonasal adenocarcinoma (LG-SNAC). Imaging and endoscopic examination revealed a pedunculated mass attached to the posterior septum, and histopathological evaluation confirmed the diagnosis. The tumour demonstrated characteristic papillary and tubular architecture, with immunohistochemical positivity for CK7 and p40 and a low Ki-67 index. The patient underwent successful endoscopic surgical resection with no need for adjuvant radiotherapy, remaining disease-free during the follow-up period. This case highlights the clinical and histopathological features of LG-SNAC and emphasises the importance of early diagnosis and surgical management. The diagnostic challenges in this case stemmed from the extreme heterogeneity and overlapping clinical presentation of low-grade non-intestinal sinonasal adenocarcinoma (LG-SNAC) with more common sinonasal pathologies. Recurrent epistaxis and nasal obstruction are frequently associated with inflammatory or vascular lesions, leading to potential misdiagnosis or delays in identifying a neoplastic process. The low-grade nature of the tumour, along with its indolent course, further complicates early recognition, making it crucial to consider LG-SNAC in the differential diagnosis for timely intervention.